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Noncaloric Drinks Promote Weight Loss in Adolescents

Am Fam Physician. 2006 Aug 1;74(3):498-499.

Soft drinks contribute 10 to 11 percent of calories to the diets of U.S. adolescents. They have been thought to promote obesity, but there are few trials examining their decreased consumption and demonstrable weight loss. Higher daily intake of sugar-sweetened beverages has been associated with obesity in observational studies, but decreasing consumption may facilitate long-term weight control. Ebbeling and colleagues attempted to determine if an environmental intervention can reduce sugar-sweetened beverage consumption and result in lower body mass index (BMI).

The study enrolled 103 adolescents 13 to 18 years of age with a BMI above the 25th percentile. Qualified participants had to drink at least one sugar-sweetened beverage daily (excluding 100 percent fruit juice) and reside in a single household. Each household received free noncaloric beverages for 25 weeks: four servings per day for participants and two servings for each additional family member per day. The individuals in the intervention group were asked to only consume these beverages while at home and to avoid sugar-sweetened beverages outside the home. The control group was instructed to continue usual beverage consumption. Instructions were reinforced with written materials and an initial telephone call. Monthly follow-up calls were conducted for the 25-week study, with the end point defined as change in BMI from baseline.

There was an 82 percent decrease in energy intake from sugar-sweetened beverages in the intervention group, but there was no change in the control group. BMI change was 0.07 ± 0.14 kg per m2 in the intervention group compared with 0.21 ± 0.15 kg per m2 in the control group. That difference was not significant, but there was a trend toward greater weight loss in participants within the intervention group who had a higher BMI and in patients with a BMI greater than 30 kg per m2. This effect was statistically significant. Additionally, participants with a BMI in the upper third at tertile (25.6 kg per m2 or higher) had a BMI change of −0.63 ± 0.23 kg per m2 compared with +0.12 ± 0.26 kg per m2 in the control groups.

Decreasing consumption of sugar-sweetened beverages affected body weight beneficially, which was strongly linked to baseline BMI, but BMI changes did not differ significantly in participants with lower base-line body weight. However, this effect was greater in patients who consumed more of these beverages. The authors suggest that, pending completion of larger studies that apply these findings, physicians and other public health professionals should continue to recommend limiting consumption of sugar-sweetened beverages.

editor's note: This study reinforces the notion that treating obesity must occur on an institutional level. First, the nature of the intervention strongly supports behavioral change; however, counseling for this change is limited. Of counseling interventions for physical exercise and eating behavior, the U.S. Preventive Services Task Force rates only intensive counseling for adults as having an evident benefit. Second, the effects of the intervention are small, and they only occur in the highest tertile of baseline weight. The likelihood is that any benefit from limiting sugar-sweetened drinks will be small. This is corroborated by observational studies1,2 that show conflicting evidence of the impact of soft drink consumption. As demonstrated in this study, public health interventions that incorporate an environ-mental rather than behavioral intervention, with a focus on small benefits for a large population, are likely to have the greatest desired impact.—c.w.